1. Field of the Invention
The present invention relates to a lock device, and more particularly to a lock device including an improved structure for selectively preventing the outdoor knob or handle from being forcedly or brutally rotated by the unauthorized persons and thus for preventing the lock device from being destroyed or damaged by the unauthorized persons.
2. Description of the Prior Art
Typical lock devices are normally attached to a door panel, and comprise a dead bolt extendible out of the lock casing for engaging with a door frame and for selectively locking the door panel to the door frame, and an indoor knob or handle and an outdoor knob or handle attached or coupled to the dead bolt of the lock device for rotating or operating the dead bolt to selectively lock and unlock the door panel.
For example, U.S. Pat. No. 3,042,437 to Duvall, U.S. Pat. No. 3,580,622 to Morgan, U.S. Pat. No. 4,496,178 to Best et al., U.S. Pat. No. 4,575,137 to Jans, U.S. Pat. No. 4,709,565 to Lin, and U.S. Pat. No. 5,551,736 to Fann et al. disclose several of the typical door lock devices each also comprising a lock casing secured to a door panel, and a dead bolt extendible out of the lock casing for engaging with a door frame, and an indoor knob or handle and an outdoor knob or handle attached or coupled to the dead bolt of the lock device for rotating or operating the dead bolt to selectively lock and unlock the door panel.
Normally, a spring biasing member is attached to the dead bolt or the handles or coupled between the handles and the lock casing for biasing or recovering the handles back to the original position and also for biasing or recovering the dead bolt to engage with the door frame after the handles are released by the user.
However, when the dead bolt is firmly or solidly locked and secured to the lock casing, the outdoor knob or handle may also be forcedly or brutally rotated by the unauthorized persons, and the inner structure of the typical door lock devices may also be destroyed or damaged by the unauthorized persons with the outdoor knob or handle.
The present invention has arisen to mitigate and/or obviate the afore-described disadvantages of the conventional lock devices for door panels.